#!/usr/bin/python
# -*- coding: UTF-8 -*-
#!/usr/bin/env python
class switch(object):
    def __init__(self,value):
        self.value = value
        self.fall = False
    def __iter__(self):
        yield self.match
        raise StopIteration
    def match(self,* args):
        if self.fall or not args:
            return True
        elif self.value in args:
            self.fall = True
            return True
        else:
            return False
operator = " + "
x = 1
y = 2
for case in switch(operator):
    if case('+'):
        print x + y
        break
    if case('-'):
        print x - y
        break
    if case('*'):
        print x * y
        break
    if case('/'):
        print x / y
        break
    if case():
        print " "